The present invention relates to electrical testing of hardware and, more particularly, to testing of hardware that contains classified or sensitive information.
Some hardware may contain classified or sensitive information which is necessary or useful in its operation. For example, a cellular phone may include encryption technology to provide privacy in making calls. This sensitive information may belong to a government, the manufacturer or the end user. If the information belongs to the end user, it may want to restrict access to the information to only a few trusted employees. If the information belongs to the government or the manufacturer, they may not want the end user to have access to it.
Devices that contain sensitive information must nevertheless be tested. Typically the end user may want to conduct these tests. For efficiency, the end user would want to use any employee capable of performing the test, without regard to their security status or the desires of the government or manufacturer, who may own the information. Thus, there is a need to test such hardware in a manner that reduces the opportunity for the tester to uncover the classified information. The protection of classified or sensitive data is also required during the repair of hardware.
Testing of hardware in an Automatic Test System (ATS) requires two basic items: (1) the Automatic Test System or test station and (2) the test program that controls the tester""s stimulus and measure instruments to verify the performance of the hardware unit under test. In general, testing of classified hardware requires that the test programs have access to the classified data stored in the hardware. That is, the classified parameters must be known and coded into the test program in order to verify that the hardware is operating according to the performance specifications. This means that the end user of the test station and test program can very easily extract the classified information. Traditionally, this situation has been handled by making the entire test station a classified item, thus making it necessary to use personnel with security clearances to test the equipment. While this is viable for domestic applications, it is very impractical for foreign users.
In order to overcome this problem, in accordance with the invention, use is made of a combination of a secured test station run time system software algorithms, hardware encoding techniques, and test program routines that ensure the safeguarding of classified data. In particular, an interface is provided that is located between the test station and the hardware being tested. The interface is constructed with knowledge of the classified information and the algorithms in the test station.
The test station is programmed by the end user with generic tests of the operating parameters of the hardware. This test information is encoded to form pseudo test signals and parameters sent to the interface so that monitoring of the control lines from the test station will not reveal the true test parameters. This may include the sending of spurious signals at certain times, which the interface is programmed to ignore. The interface is also connected to stimulus and measurement equipment in the test station which provide test signals and measure the response of the hardware to those signals. The interface encodes the test results and sends them back to the test station for evaluation as to whether the hardware is operating properly or not.